Many motorized moving pieces of home automation equipment, in particular screens, blinds and rolling shutters of all types, are equipped with a backup manual driving device with a crank, the latter driving an intermediate gear reducing stage such as a worm, designed to drive the moving element of the home automation equipment if the motor fails. One example of such a device is given by document FR 2,480,846. On the one hand, the device includes a motorized drive device, or actuator, with an electric motor and a tubular casing designed to be housed in a rolling tube for blinds, shutters or similar members, and on the other hand includes a mechanism that can be actuated manually, capable of rotating the tubular case of the motor. The driveshaft of the actuator is kinematically rotatably connected to the winding tube, a first device being provided to immobilize the rotation of the case, such that when the motor is operating, the output shaft of the actuator rotates the winding tube around the case. A second device is provided to immobilize the rotation of the winding tube relative to the tubular case, such that when the motor is not operating, the winding tube can be driven manually by the rotation of the tubular case of the actuator around itself. The mechanism able to be actuated manually includes a drive wheel secured in rotation with the tubular case and concentric thereto, driven by a worm formed at the end of a rod driven by a crank. The rod and the worm being formed in a single piece, it is not possible to choose the length of the rod based on the installation conditions of the apparatus, or to completely omit it if it is unwanted in certain applications.
The search for delayed industrial differentiation between different versions proposed within a line of equipment leads to separating the worm from the rod, as for example proposed in document EP 2,503,091, which shows a worm passed through by a hole with a hexagonal section allowing the insertion of a rod with a complementary section, the final axial position of which is determined by an annular washer. However, this assembly must nevertheless be done in the plant, since the operation requires opening the cover of the mechanism and is outside the scope of the installer's responsibility. The rod is therefore part of the complete shipped mechanism assembled by the manufacturer. The bulk of the preassembled mechanism results in high packaging costs, and risks of breaking during transport and handling.